Over the years, anabolic agents have been heavily used as an aid in increasing the rate of growth in meat-producing animals. However, a drawback of such previously used compounds is that in addition to their anabolic activity, they possess some degree of hormonal activity. As a consequence, animals treated with these compounds tend to produce relatively high levels of fat as compared to the amount of muscle. Thus, while the early anabolic compounds may have achieved some degree of success in terms of weight gain, their hormonal properties resulted in weight gain which was of little economic value since a significant portion was due to the presence of fat.
In recent years, further concern has arisen over the use of these compounds in animals due to the possible estrogenic effect of these compounds on humans consuming the meat of these animals. As a result of this concern, one such common agent, diethylstilbestrol, is no longer sanctioned for use in animals in order to prevent entry of these compounds into the human food chain.
Another disadvantage of many anabolic compounds is that they often possess anti-bacterial activity. As a result, their use in animals may have a side affect wherein the natural balance of bacterial flora of the animal is disrupted. Such a change in the bacterial flora could be especially significant in ruminant animals where these compounds may disrupt the delicate ecological balance of bacterial flora in the rumen needed to insure the health and well being of the animal.
As a result of the many side effects associated with these early compounds there is a need for new anabolic compounds which lack undesirable hormonol activity.